FAQ: How do I choose the right filter for my aquarium


How do I choose the right filter for my aquarium?
All aquariums require a filter system to maintain high water quality and healthy fish. Mechanical Filtration
uses a material like a filter pad to remove particles from water.
Water passes through the pad and particles are trapped. This keeps the
water from being silty or cloudy. Chemical filtration uses
absorption to remove chemcial compounds from the water. Carbon and Poly
Filters are the most common chemical filters. Both types need to be
routinely replaced. Finally, biological filtration, the most
important, is required. Fish release ammonia and if that ammonia is
allowed to build up in the aquarium, it can kill fish. “Good” or
beneficial bacteria use a biological oxidation prodcess to filter water
and convert it from ammonia-laden to something less toxic. Biological
filtration is a LIVE filter.

Power Filters: Power and canister filters push or
pull water through a set of media in a container with a motorized pump.
An uptake tube pulls water through the unit. The water then passes
through various media before being expelled to the aquarium again.
Power filter that attach, or hang onto the back of the aquarium are
small and inexpensive. Canister filters are sealed, pressurized and are
placed beneath the aquarium, inside the aquarium stand. Because of the
powerful water movement, these filters can be used on large tanks. With
quick disconnecting hoses, it is easy to perform maintenance by taking
the filter to the sink, so that water is not spilled.

Wet/Dry or Trickle Filters
Trickle filters
(usually a rectangular glass or acrylic box) have evolved from standard
filters and tend to be more efficient while taking up less space. The
basis on which they function is by housing biological substances in a
filter chamber and as water is dripped or sprayed over it, large amounts
of beneficial bacteria grow. Due to the high contact of air to the wet
substance, the bacteria grow in a wet-dry, highly oxygenated state.
Most trickle filters use a filter fiber as a pre-filter. This handles
most of the mechanical filtration. Some examples of biological
substances used for filtration include Bio-balls, DLS material, and

Trickle filters are large, so like canister filters they are typically
located underneath the tank, inside the aquarium stand. Water from the
aquarium is allowed to “overflow” down a standpipe inside the aquarium
to the trickle filter and then is returned to the aquarium by means of a
water pump.

Protein Skimmers
Protein skimmers are a great development in keeping saltwater aquariums.
They have made it possible to maintain very high levels of water
quality for extended periods of time. Protein skimming may also be known
as foam fractionation, and the concept behind it has been in use for

Protein skimmers work quite simply. Foam is created by mixing saltwater
and air together—the finer the mix and the smaller the bubbles, the
more efficient the skimmer will work. Proteins and other organic
molecules stick to the bubbles, which creates a stable foam that rises
above the mixing air and water. This foam is then gathered before it is
returned to the tank.

The wastes, organics, and proteins that are collected are pulled out
before they have a chance to break down. This basically cleans the
water, almost by scrubbing, removing all manner of waste materials from
the aquarium and making the biological filter more efficient.

UV Sterilizers
Finally, Ultraviolet sterilizers pass
water through a sealed tube with an ultraviolet light; the light gives
off rays that sterilize or alter the DNA of living organisms that pass
by it. Because this is fed by a pump with a pre filter, large animals
(like fish, etc.) are not harmed. Bacteria, protozoan, algae cells and
parasites are all killed with this method. The key to using one of these
is to size it correctly to the tank.

UV sterilizers are generally use an in-line connection between the
aquarium and the filter system. The U.V light bulb is effective for
about 6 months and then needs to be replaced.